Dear Rovers North,
A few weeks ago, I emailed regarding oil usage on a ’04 Discovery Series II. I was using 3.5 quarts every 6,000 miles without blue smoke, etc. I believe that I have finally found the issue. After looking inside the air intake with the butterfly flap open, I noticed dark oil residue on the inside of the intake where the passenger side valve cover vents into the intake. The other side was clean. After researching the design of the valve cover, it appears that Bosch removed the typical PCV valve. The small hole on the vent stack (where the rubber hose attaches on the valve cover) should serve like a PCV valve (by regulating the gasses into the intake). However, the continuous air flow through the intake draws air in from the value cover and thus oil vapor/mist with it.
After putting on a PCV valve downstream from the valve cover vent stack, oil consumption was zero in one day. It has been 1/8th quart or more every day over a hundred miles. (…)

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